全文获取类型
收费全文 | 3561篇 |
免费 | 100篇 |
国内免费 | 14篇 |
专业分类
化学 | 2458篇 |
晶体学 | 22篇 |
力学 | 42篇 |
数学 | 507篇 |
物理学 | 646篇 |
出版年
2022年 | 23篇 |
2021年 | 25篇 |
2020年 | 44篇 |
2019年 | 52篇 |
2018年 | 23篇 |
2016年 | 70篇 |
2015年 | 73篇 |
2014年 | 89篇 |
2013年 | 107篇 |
2012年 | 148篇 |
2011年 | 180篇 |
2010年 | 110篇 |
2009年 | 83篇 |
2008年 | 121篇 |
2007年 | 154篇 |
2006年 | 174篇 |
2005年 | 162篇 |
2004年 | 105篇 |
2003年 | 101篇 |
2002年 | 103篇 |
2001年 | 91篇 |
2000年 | 68篇 |
1999年 | 55篇 |
1998年 | 53篇 |
1997年 | 48篇 |
1996年 | 58篇 |
1995年 | 71篇 |
1994年 | 58篇 |
1993年 | 54篇 |
1992年 | 66篇 |
1991年 | 37篇 |
1990年 | 40篇 |
1989年 | 38篇 |
1988年 | 50篇 |
1987年 | 56篇 |
1986年 | 36篇 |
1985年 | 49篇 |
1984年 | 40篇 |
1983年 | 31篇 |
1982年 | 36篇 |
1981年 | 43篇 |
1980年 | 48篇 |
1979年 | 34篇 |
1978年 | 40篇 |
1977年 | 41篇 |
1976年 | 43篇 |
1975年 | 42篇 |
1974年 | 50篇 |
1973年 | 43篇 |
1971年 | 27篇 |
排序方式: 共有3675条查询结果,搜索用时 46 毫秒
71.
On the Reaction of Nb3Cl8 with HCl The greenish-blue gas phase which is formed at 500–600°C by reaction of Nb3Cl8 with HCl, is caused by an equilibrium reaction, in which small amounts of NbCl5 and larger amounts of NbCl4 are formed. This is shown by photometric measurements and by thermodynamic calculations. 相似文献
72.
73.
Harald Stueger Markus Braunwarth Gottfried Fuerpass Judith Baumgartner Robert Saf 《Monatshefte für Chemie / Chemical Monthly》2006,137(5):595-603
Summary. The previously unknown ruthenio disilanes Rp–Si2Me4–C6H4X (Rp = η5-C5H5Ru(CO)2; X = H, Br, –CHO, CH=C(CN)2) were synthesized from ClSi2Me4C6H4X (X = H, Br) and Rp− using conventional chemical methods. Trends in the UV/Vis absorption spectra indicate strong electronic coupling within the
Rp–Si–Si–Caryl fragment and, therefore, closely resemble the ones observed for the corresponding iron complexes. The four compounds however,
were shown to be less sensitive towards UV irradiation. The crystal structure of Rp–Si2Me4–C6H4CH=C(CN)2 was determined by X-ray diffraction and exhibits an all-trans-array of the Ru–Si–Si–Caryl moiety, what is a basic requirement for optimal through-bond interaction. 相似文献
74.
At a pressure of 10?6 Torr the ion cyclotron resonance spectra of p-benzoquinone, methyl-p-benzoquinone, tetramethyl-p-benzoquinone and tetrafluoro-p-benzoquinone are identical to the normal mass spectra. Above 10?5 Torr the spectra show a variety of signals for product ions. From double resonance measurements it was shown that all the product ions are formed by addition of the molecular ion or of a fragment ion to a neutral quinone molecule. In most cases the addition is accompanied by the elimination of carbon monoxide. 相似文献
75.
Harald Löwe 《Geometriae Dedicata》1995,58(1):45-51
We construct symmetric planes associated with an arbitrary locally compact connected nearfield
. If
is a proper nearfield, i.e.
{;;}, then the tangent translation plane of this symmetric plane is not classical. All previously known examples of symmetric planes have classical tangent translation planes.Herrn Professor Dr. H. Salzmann zum 65. Geburtstag gewidmet 相似文献
76.
77.
McFarland KS Naples D Arroyo CG Auchincloss P de Barbaro P Bazarko AO Bernstein RH Bodek A Bolton T Budd H Conrad J Drucker RB Harris DA Johnson RA Kim JH King BJ Kinnel T Koizumi G Koutsoliotas S Lamm MJ Lefmann WC Marsh W McNulty C Mishra SR Nienaber P Nussbaum M Oreglia MJ Perera L Quintas PZ Romosan A Sakumoto WK Schumm BA Sciulli FJ Seligman WG Shaevitz MH Smith WH Spentzouris P Steiner R Stern EG Vakili M Yang UK 《Physical review letters》1995,75(22):3993-3996
78.
F. Reinert P. Steiner Th. Engel S. Hüfner 《Zeitschrift für Physik B Condensed Matter》1995,99(2):223-227
Electron-energy loss spectra of potassium permanganate (KMnO4) with primary electron energies 25 eV<=E0<=500 eV show 7 peaks in the energy-loss range 1 eV<=ΔE<=10eV and are successfully analysed with a superposition of 7 independent Gaussians. The intensity of these lines follow roughly a power-law dependence on the primary energy I∝E 0 -α . There are two groups of lines, the first with an exponent α≈0.5, while the lines in the second group decay much stronger with increasingE 0 corresponding to a value 0.9<=α<=1.3. The 4 lines in the first group are identified as dipole allowed transitions by comparison to recent first principle molecular-orbital calculations for the (MnO4) molecule by H. Nakai et al. The dipole-allowed excitation spectrum obtained from this analysis agrees very well with these first principle calculations. 相似文献
79.
80.